1. Field of the Invention
The present invention falls within the field of transporting and handling loads, in particular loading and unloading a load exclusively of the container type.
The invention will preferably, but non-limitingly, be applicable to transporting and handling containers within a port zone.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
The In a known manner, a container is an enclosure with standardized dimensions, assuming the form of a parallelepiped block and making it possible to load goods therein for storage and transport, in particular by sea on boats called “container ships”.
More specifically, such a container comprises a rectangular parallelepiped structure, each corner of which is equipped with a standardized steel corner, called “ISO corner”, connecting vertical metal uprights. Thus, it is possible to stack several containers on top of one another, forming a storage zone. The stacking is done by lifting vehicles from transportation vehicles provided with a platform for receiving one or more containers, and vice versa during unstacking. These operations are carried out by means of a station, or dock, receiving one or more containers so that they can be loaded or unloaded on the platform of the vehicle, or reciprocally during unstacking or stacking from and to the storage zone.
More specifically, a station is made up of at least two guideways extending horizontally, parallel to one another. These guideways have an L-shaped section, turned toward one another, and spaced apart to receive the standardized width of the containers, in order to constitute flat lower longitudinal bearing zones on which the containers rest that are loaded there by the lifting vehicle from the storage zone and unloaded from the vehicle.
In both cases, said vehicle becomes placed within the space arranged between and under the guideways. To that end, the station is raised by means of bases or feet extending vertically and connecting each guideway in the upper portion and at regular intervals. Thus, the vehicle can be positioned below the guideways, in order to load or unload its containers.
It will henceforth be noted that the width of the spacing between the bases and the guideways that they support depends on the standardized width of the containers. Furthermore, given that the vehicle receives one or more containers on its rear platform, its chassis has a width equivalent to their width, but slightly smaller, to be able to perform the positioning maneuvers in order to be inserted, parked and removed from the station. These size constraints require precision in the driving of each vehicle and dexterity from the driver, causing a non-negligible loss of time if the latter is required to start over several times, or risking colliding with the bases of the station and damaging it, as well as the vehicle.
Since the station is raised, the platform of the vehicle is configured as a lift table so as to go from a lower position to an upper position, and vice versa. In the lower position, the height of the platform allows it to pass below the guideways, while in the upper position, the vertical travel of said platform allows it to come above the latter. Furthermore, the lifting means of the vehicle are situated in a centered manner, so as to be deployed and folded back into the space separating said guideways.
More particularly, during the loading of at least one container deposited beforehand on the guideways of the station, the vehicle positions itself within the station, below the guideways. Then, its platform is actuated to raise and lift the container, which then no longer rests on the guideways. Next, this vehicle leaves the station and once again lowers its platform.
During unloading, before positioning itself within the station, the vehicle lifts its platform and the container that rests on top of it. It then parks its chassis below the guideways to next lower the platform again to the lower position, then allowing the container to rest on the guideways. Lastly, it leaves again empty with its platform lowered.
Furthermore, the storage zone being situated at one end of the station, or a set of several stations, the vehicle must park itself in reverse from the opposite end. Once the loading or unloading is done, the vehicle then leaves again by driving forward.
In particular, each vehicle is positioned within a waiting zone, situated near each station, opposite the storage zone. Such a zone extends substantially aligned with each station, forming a circulation corridor. Access to this corridor is allowed by the free space situated between said waiting zone and said station. Thus, a vehicle positions itself in the forward direction within the waiting zone, to next leave in reverse toward the corresponding station by following said corridor.
It will be understood that these maneuvers require great precision to position the vehicle in the station, between the bases and below the guideways, to align perfectly with the latter, so that the container rests on both sides of said guideways, or is perfectly aligned with the platform that will lift it. Such precision has required the implementation of a complex system for automatically guiding vehicles. Furthermore, such a system uses electronic guidance of the vehicle, in particular wire-guided guidance.
Then, from this perspective, the vehicles have been completely automated, eliminating the presence of a driver and a driver station. Thus, said vehicles are similar to motorized platforms, completely independent and controlled by a complex computer system, managing the entire fleet of vehicles for the facility, in particular the port facility. In all, the guidance system is deployed over the entire surface of this port, ensuring the controlled automatic movement of all of the vehicles, in a manner coordinated with one another.
Although such automation, eliminating the human driver, ensures perfect guidance and positioning of the vehicles, it nevertheless has a major drawback. Vehicles moved automatically can only be moved at a limited speed, in order to avoid or anticipate any accident risk. Currently, the travel speed of such automatic vehicles is approximately 5 kilometers per hour (km/h). Given that the entire port fleet is controlled automatically, all of the vehicles travel at the same speed. While this slowness is necessary when each vehicle is being positioned precisely within a station for loading or unloading, it is detrimental in other zones where the vehicles pass, and due to the absence of a driver, it is not possible to consider accelerating the speed for obvious safety reasons.
Furthermore, the vehicles are conveyed along specific circuits extending along guidance means. Although several alternative circuits are possible, no change in trajectory can be considered outside these paths. Flexibility is therefore greatly limited.
Furthermore, in order to avoid collision risks, the circuits are completely reserved for the movements of these automatic vehicles, prohibiting access by people and other types of vehicles. This reservation causes considerable loss of the total space of the port zone. Furthermore, it is necessary to arrange the infrastructure to physically model these spaces reserved for automatic circulation, also creating complexity in its implementation and overlapping of the automatic and non-automatic circuits.
One example of such a solution, specifically targeting the transportation and handling of heavy trucks, with or without trailers, is described in document EP 1,480,097. One can see fully automated guidance, of the wired type, within a zone from an entrance toward an exit, such that each vehicle passes through several stations, always traveling in the forward direction.
In this context, it has been imagined to optimize the circulation of vehicles by combining automatic vehicle guidance with manual driving, reciprocally ensuring precise movements at a safe speed during loading and unloading around the stations and a possibility of increasing the movement speed outside the zones.
Document EP 0,324,083 describes one example system for guiding a transportation and handling vehicle on an aeronautics site. Such a vehicle is guided by a wired system to be positioned automatically in the vicinity of an aircraft, in order to perform a lifting operation of its rear platform, designed to support a case containing baggage. The precision of the guidance must allow the vehicle to position itself perfectly, such that, during the lifting operation, the rear of the platform is as close as possible to the cockpit of the aircraft, across from the access hatches to the cargo bay, but without touching it, which could damage it.
Furthermore, during parking, several vehicles are guided in reverse to be parked parallel to one another, orthogonally and abutting by the rear against the edge of the loading dock, then only requiring precise positioning to stop the rear vehicle as close as possible to said dock and guidance to orient the vehicles parallel to one another.
Outside the vicinity of an aircraft or the loading dock, the vehicles are controlled manually by their driver.
However, this solution is used in the context of an airport, with specific constraints regarding the type of goods to be transported, i.e., baggage, the weight and volume of which is limited, transportable within boxes that can be moved manually.
An alternative guidance technique is described in document WO 2010/064989, allowing the driver to receive driving instructions to park his truck in reverse, orthogonally abutting against a loading dock. This solution is similar to a backup radar, but instead of equipping the truck, it is the loading dock that emits a signal to detect the position of the back of the trailer during reverse maneuvers, to communicate driving instructions to the driver.
Once again, this solution depends on the dexterity of the driver to drive his truck and follow the guidance instructions perfectly.
Furthermore, not all of the existing solutions need precision in the lateral guidance of the vehicle, to be inserted into a confined space with a limited width, so as next to be able to raise or lower its rear platform to go between the guideways of a container handling station.